With a rapid development of display technology, the demand for display technology has become higher and higher. Currently, micro-projection technology has started to be marketed, and widely used in personal consumption field and business situation, which has a broad development prospect.
Micro-projection technique is mainly based on Liquid Crystal on Silicon (LCoS) which is a novel reflective display technique organically binding an LCD and a CMOS integrated circuit. The display principle of the LCoS is similar to the display principle of LCD, that is, the display image can be controlled by polarized light modulation. The current color realization of the LCoS is mainly based on timing technique, which can sequentially form cyclical R, G and B three primary colors from white light by rapidly rotating a color wheel; during display, about 67% of light energy will lose and the light utilization efficiency is low. Micro-projection system generally uses batteries to supply power, and power consumption is restricted, thereby the brightness of the projection system is limited. Moreover, the color wheel can only be arranged outside of the LCoS, which is complicated in structure and thus the volume of the projection system is large. Therefore, the key point in the research of the LCoS is to improve the optical efficiency of the projection system and reduce the volume of the projection system.